Fermented sausages are dry cured sausages
Sausage
Recipes
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Traditionally Made Fermented Sausages
Bacteria -
Yeasts - Molds
Bacteria Survival Tables
USA & Canadian Fermentation Standards
Starter Cultures
Safety Hurdles
Equipment
Fermented sausages
are dry cured sausages and to produce salami of a
consistent quality one must strictly obey the rules of sausage
making. There is little information on the Internet on
making fermented sausages and most books on sausage making do not
tackle this subject either. One can obtain some recipes and with some luck
can produce salami at home. The problem is that the next time you try to
produce salami it will
turn out different even if the same recipe was used. This can be compared to
a cripple following a blind man, they will never walk the same path twice. There are a few
stages of making a fermented sausage and a serious violation of
established rules will spoil the product and may even make it
dangerous to consume. As some sausages, notably slow fermented ones,
take many weeks or even months to produce it is a great loss to waste so much time
and investment due to insuffiicient know-how or one's negligence.
This field of knowledge has been limited to just a few lucky ones but with today's
meat science and starter cultures available to everybody, there is
little reason to abstain from making quality salamis at home. It is
unlikely that a home sausage maker will measure meat pH (acidity) or Aw (water
activity) but he should control temperatures and humidity levels in his
drying chamber. Followed below there is a lot of meat
science pertaining to the manufacture of fermented sausages which we tried
to make as simple as possible. By reading this material one can get a
very good idea and understanding of the process.
There is a difference in fermented sausage technology
between the United States and the European countries. American methods
rely on rapid acid production (lowering pH) through a fast fermentation
in order to stabilize the sausage against spoilage bacteria. Fast acting
starter cultures such as Lactobacillus
plantarum and Pediococus
acidilactici are used at high temperatures up to 40º C (104º F).
As a result pH drops to 4.6, the sausage is stable but the flavor
suffers and the product is sour and tangy. In European countries, the
temperatures of 22º -26º C (72º
-78º F)
are used and the drying, instead of the acidity (pH) is the main hurdle
against spoilage bacteria which favors better flavor development. The
final acidity of a traditionally made salami is low (high pH) and the sourly taste is gone.
Some known European sausages are French saucisson, Spanish
chorizo, and Italian salami. These are slow-fermented sausages with
nitrate addition and moderate drying temperatures. North European
sausages such as German or Hungarian salamis are made faster, with
nitrite addition and are most often smoked.
Fermented sausages can be divided into two groups:
Sliceable raw sausages
(Salami, Summer Sausage, Pepperoni))
Spreadable raw sausages
(Teewurst, Mettwurst)
Salamis can be divided into:
fast-fermented
medium-fast-fermented
slow-fermented:
with mold
without mold (often smoked)
or as:
moist - 10% weight loss
semi-dry - 20% weight loss
dry - 30% weight loss
There is also a group of
non-fermented cooked salamis that are made in many European
countries. This group will cover any sausage that is smoked, cooked
and then air-dried for 1-3 weeks at 10º-12º
C (50º-52º
F). This reduces Aw (water activity) to about 0.92 which makes the
product shelf stable without refrigeration. The fact that a raw
sausage is safe to consume may sound questionable to some but we have been
eating them for thousands of years and as far as we follow the rules
of meat science we have nothing to be afraid of.
The Magic Behind Fermented Sausages
- It's All About Bacteria
We all know that meat left at room temperature
will spoil in time and that is why it is kept in a
refrigerator/freezer. Yet fermented or air dried sausages are not
cooked and don't have to be stored under refrigeration. What makes
them different?
Meat contains about 75% of water and this moisture is
the main reason why it spoils. Ever present bacteria will jump
into this pool of water and will double up every 20 minutes if the
temperature approaches 34º C (90º F). In a
refrigerator their number will also grow albeit at a reduced pace but
they will double up in 12 hours. Eating contaminated meat is bad for
us and we get sick, in severe cases we may even die. Bacteria hate cold
conditions and most of them lie dormant at low temperatures waiting for an
opportunity to jump into action when the weather gets warmer again. Most
of them die when submitted to a cooking temperature of 160º F (72º C) The
fully cooked meat has to be refrigerated as new bacteria
will invade the previously cooked meat piece and will start spoiling it
again. Fighting bacteria is a no-win
battle but at least we can do our best to turn the odds in our favor
and make life miserable for our enemy.
Fermented sausages and air
dried meats are at an extra risk as they are not subject to cooking/refrigerating process.
In a freshly filled with meat casing, bacteria seem to hold
all advantages: temperatures that favor their growth, moisture,
food (sugar), oxygen, we have to come up with some radical
solutions otherwise we might lose the battle. Fortunately, meat
science is on our side and what was a secretive art for many years is being revealed and made accessible to everybody today.
Even so, manufacture of fermented products is still a combination of an
art and technology.
Meat of a healthy animal is clean and has no bacteria. Bacteria which is present everywhere are introduced when we start to process meats:
every time a knife cuts meat, the blade introduces new bacteria which
multiply and slowly migrate towards the inside of the piece. As more cuts
are made, the easier it is for bacteria to penetrate the piece. This
is why ground meat (small particles) has the shortest shelf life. A
meat processing facility develops its own microbiological flora in
which bacteria live all over the establishment (walls, ceilings,
machinery, tools etc). Each place will have its own peculiar flora
and some places will contain more bacteria which is needed for
making fermented sausages. Keep in mind that in the past meat
facilities were not sanitized so
scrupulously
as the ones of today. These bacteria are just waiting to jump
on a new piece of meat and start working in. All they need is a bit
of food: moisture (meat is 75% water), oxygen (the air) and sugar
(meat contains sugar). Sugar has been introduced into sausage
recipes for hundreds of years as somehow we have always known that
it is needed. Some places in Italy had inside flora which was
beneficial to produce a product of a great quality and they
suddenly developed a name for making wonderful meat products. They were probably not better
sausage makers than their counterparts working in different
locations. Most likely they were lucky to have their shop located in
their area which was blessed by mother nature for making
fermented sausages. They did not have much clue to what was
happening, this empirical knowledge was passed from father to son
but it worked like magic.
Fermented sausages are made by use of
"beneficial or friendly" bacteria that we manipulate to our advantage and they
become microscopic laborers performing tasks that we can not do
ourselves. They are the tiny soldiers and we are the command center and
if we manage this army well they become a formidable force. All this bacteria talk should not alarm anybody as we are
surrounded with fermented foods: sour bread, wine, yogurt,
sourkraut, cheeses, etc.
Some of the most dangerous bacteria (E.coli
and Listeria monocytongenes) live in
our digestive tract and help us to digest foods, other (Staph.aureus)
are present in our skin, mouth and nose. The most toxic poison known to men is in soil (Clostridium
botulinum) and we touch those spores every time when working
the garden, yet we are perfecly fine. Dangerous bacteria are present in
meat and we eat them every time when undercooked meat is served
and that does not seem to affect us either. This is due to the
small number of bacteria present and if their number were higher our
immune system would not be able to fight them off.
In regards to sausage making we could divide bacteria
as:
Spoilage
Dangerous
Beneficial
These bacteria cause food to deteriorate and
develop unpleasant odors, tastes and textures. These one-celled
microorganisms can cause fruits and vegetables to get mushy or
slimy, or meat to develop a bad odor. Most people would not
choose to eat spoiled food. However, if they did, they probably
would not get sick.
These are known as pathogenic bacteria and
they cause illness. They grow rapidly in the "Danger Zone" - the
temperatures between 40º and 140º F (4-60º C) - and do not
generally affect the taste, smell, or appearance of food. Food
that is left too long at unsafe temperatures could be dangerous
to eat, but smell and look just fine. E.coli 0157:H7
(Most illness has been associated with
eating undercooked, contaminated ground beef),
Campylobacter (Most cases of illness are associated
with handling raw poultry or eating raw or undercooked poultry
meat), and Salmonella ( Salmonella
is usually
transmitted to humans by eating foods contaminated with animal
feces. They are often of animal origin, such as beef, poultry,
milk or eggs.
Chicken meat is known to contain more
Salmonella than other
meats. Staph.aureus is
hard to control and to inhibit its growth Aw must be lower
than 0.89 and pH below 5.2. Cl.botulinum, very toxic and heat resistant,
likes moisture but hates oxygen.
These bacteria can be managed to
our advantage to produce fermented sausage. They are naturally
occuring in meat and are responsible for:
converting nitrate to nitrite: (Micrococcus,
Staph.xylosus,
Staph.carnosus)
improving flavor:(Micrococcus,)
increasing acidity (lowering pH) by
producing lactic acid through sugar metabolism: (Pediococcus
and Lactobactillus)
mold growth: (Penicillium
nalgiovense) which is highly desired in some
Italian salamis.
Looking at the table it is quite
obvious that in order to produce a quality safe product it is
necessary to:
prevent the growth of spoilage bacteria
prevent the growth of dangerous
bacteria
create favorable conditions for the growth of
beneficial bacteria
More about pathogenic bacteria at:
http://www.wedlinydomowe.com/fermented-sausages/bacteria-yeasts-molds.htm
More about spoilage bacteria at:
http://www.wedlinydomowe.com/sausage-safety.htm
To eliminate the risk of bacteria growth and to
prevent meat spoilage we employ the following steps, also known
as "hurdles":
using meats with a
low bacteria count
curing - adding salt and
sodium nitrite/nitrate
lowering pH of the meat
to 5.2
lowering Aw (water
activity) by drying to
0.89
smoking
1. Meat selection is the
first step to a successful production of a fermented sausage. Going into details on selecting meats
according to their pH or using terms like PSE, GFD or
MDM meats is beyond the scope of these pages and will make them
confusing to read. What we want to stress is that meat must be perfectly
fresh with the lowest count of bacteria possible.
Commercial producers try to keep this number between 100 and 1000
per gram of meat but a home based sausage maker has to make sure
that:
meat is very fresh and kept
cold
facilities and tools are very
clean
working temperatures are as low
as possible
If the above conditions are not met bacteria will multiply and will
compete for food with starter cultures inhibiting the growth. As a result, the product will fault, especially the
slow-fermented salami. It makes little difference to what kind of
meat is used and salamis can be made from pork, beef, venison,
buffalo, horse and other meats. If chicken is used the thigh (dark
meat) will be the better choice than a breast (light meat). Chicken
breast being light meat contain little myoglobin that reacts with
nitrite to produce curing color and the finished sausage will have a
very light pink color unless chicken meat will be mixed with darker
meats. Keep in mind that chicken meat has higher chances to be
infected with Salmonella than
other types of meat. Also remember that raw pork or venison meat may be
infected with trichinosis so please read the following link to
be safe: trichinae
Typical values of meats selected for commercial production are:
pork: pH-<5.9-6.0, beef: pH-<5.8 and Aw- 0.98 - 0.99
2. Curing. The application of
salt and nitrite is actually our first line of defense against
the growth of spoilage bacteria as in many cases (home production)
there is very little we can do about a selected meat's bacteria
count except making sure that the meat is fresh. As the
sausage slowly dries out it loses moisture but not the original amount
of salt which remains inside. As a result, in time the sausage
becomes much saltier to bacteria. In about 3-6 days the Aw
drops to about 0.95 and the sausage is microbiologically more stable
as some pathogenic bacteria (for example
Salmonella) stop multiplying now. Using a combination of different hurdles is
more effective that relaying on one method only. For example the
first hurdle is an application of salt and sodium nitrite which
eliminates some of the microbiological spoilage. This will not
be enough to produce a stable sausage if we don't follow up with
addidional hurdles such as lowering pH (increasing acidity) and then lowering water
activity Aw (eliminating moisture by drying).
Salt. In the right part of the table below it can be seen
that most bacteria can tolerate water activity levels (Aw) up to 0.92.
For example Clostridium botulinum (food poisoning) bacteria are active
all the way down to 0.93 Aw. The table on the left below depicts that to
bring water activity level down to 0.93 level about 10 % salt solution
is needed. We will have to add 100 g of salt to 1 kg of meat to be sure
that Clostridium growth will be inhibited. But any salt level above 3 %
will make meat unpalatable to most people so salting alone will not cut
it. Additional hurdles such as lowering water
activity and lowering of pH (increasing acidity) will have to be implemented.
Hundreds years ago heavy salting was commonly used to preserve and to
transport fish to different countries but that fish was non-edible in its
original state. It had to be soaked in water first to eliminate an
excess salt and only then it would be cooked. The more salt applied to
meat the stronger fence is created against bacteria and some compromise
has to be made as the salt plays a very important role preventing
bacteria growth, especially in the first stages of a process.
At least 2.5 % salt (25 g salt/1 kg of meat)
should be added which will help to lower water activity and inhibit
the growth of bacteria.
Sodium nitrite/nitrate is added to the majority of
salamis to suppress the growth of Salmonella or eliminate the danger
of Clostridium botulinum. It also contributes to
the development of the
desired curing color and curing flavor. A combination of nitrite and
nitate (Cure #2) is applied to slow fermenting products as nitrate
guarantees a stable color even after drying for some months.
3. ph
Foods with a low pH value (high acidity) develop
resistance against microbiological spoilage. Pickles, sourkraut,
eggs, pig feet, anything submerged in vinegar will have a long
shelf life. Even ordinary meat jelly (headcheese) will last longer
if some vinegar is added and this type of headcheese is known as "souse". Bacteria hate
acidic foods and this fact plays an important role in
the production and stabilization of fermented sausages. Ideally the pH
value of meat to be used for making fermented products should be
below 5.8.
Pork
5.9 - 6.0
Back fat
6.2 - 7.0
Emulsified pork skins
7.3 - 7.8
Beef
5.8
Combining different meats will have an effect on the final pH value of
the sausage mass.
pH meat tester available from QA Instruments,
http://www.qasupplies.com/
pH
testing paper strips made by: Micro
Essential Laboratory,
Inc.,
www.microessentiallab.comTo use, mix 1 part finely chopped meat
and 2 parts distilled water, tear off a strip of pH
paper, dip into test solution, and match immediately to
color chart. No technical training is necessary.
Available from: www.butcher-packer.com
Sugar, Glucono-δ-lactone
(GDL)
and Citric Acid are important additives in the manufacturing of fast and
medium-fermented salamis as in these sausages pH reduction
(increasing acicity) is the main hurdle against bacteria growth. In
slow-fermented sausages which are dried for a much longer time,
lowering moisture (Aw) is the main hurdle employed to inhibit
bacteria growth.
Glucono-delta-lactone
is manufactured by microbial fermentation of pure glucose to
gluconic acid but is also produced by the fermentation of
glucose derived from rice. It is soluble in water and is non-toxic
and completely metabolized in our bodies. It can be found in honey,
fruit juices, wine and many fermented products. It is a natural food
acid (it has roughly a third of the sourness of citric acid) and it
contributes to the tangy flavor of various foods. Since it
lowers the pH it also helps preserve the food from
deterioration by enzymes and microorganisms. It is metabolized to
glucose; one gram of GDL is equivalent to one gram of sugar.
Glucono-Delta-Lactone is often used to make cottage cheese, Tofu,
bakery products and fermented sausages.
About 1 g (0.1%) of GDL per 1
kg of meat lowers pH of meat by 0.1 pH. It shall be noted
that the addition of sugar already lowers the pH of the meat and
adding GDL will lower the pH even more. As it is a natural acid, adding
more than 10 g may cause a bitter and sour flavor.
Citric acid is a
weak organic acid found in citrus fruits. It is a natural
preservative and is used to add an acidic (sour) taste to
foods, soft drinks and wine. In lemons and limes it can account for
as much as 8 % of the dry weight of the fruit. Citric acid is
mentioned in these pages more for its informational value in
lowering pH than by its practical usefulness in making fermented
sausages. It acts about three times faster than GDL
(1 g of citric
acid added to 1 kg of meat lowers ph of meat by about 0.3 units)
and in higher doses it will contribute to a sour taste. Its usefulness is
therefore strictly limited.
Sugar is mainly added to provide food for starter
cultures. The pH drop in sausage depends on the type and
amount of sugar utilized. Introduction of more sugar
generally leads to lower pH and stronger acidification. What is notable
is that lactic bacteria process different sugars differently. Only
dextrose (glucose) can be fermented directly into lactic acid and by all
lactic bacteria. Other sugars molecular structure must be broken down
until monosaccharides are produced and this takes time and some lactic
bacteria are more effective than others. Sugar introduction also helps to offset
the sourly and tangy flavor of fastand
medium-fermented sausages and acts as a minor hurdle in lowering
water activity. The types of sugar which may be used in making fermented
sausages are listed in order of their importance on producing lactic
acid by lactic acid bacteria:
glucose - "dextrose" is glucose sugar refined
from corn starch which is approximately 70% as sweet as sucrose but
it has an advantage of being directly fermented into lactic acid and
is the fasted acting sugar for lowering pH. As
lowering pH is the main hurdle against bacteria growth in
fast-fermented sausages, dextrose is obviously
the sugar of choice. It can be easily obtained from all sausage equipment and
supplies companies.
sucrose - common sugar (also colled
saccharose) made from sugar cane and sugar beets but also appears in
fruit, honey, sugar maple and in many other sources. It is the
second fastest acting sugar. It can be used with GDL in
medium-fermented sausages. In slow-fermented sausages common sugar should be chosen as it has been used
for hundreds of years. There is no need to lower fast pH and
sugar contributes better to a strong curing color and better
flavor.
maltose - malt sugar is made from germinating
cereals such as barley, is an important part of the brewing process.
It's added mainly to offset sour flavor and to lower water
activity.
lactose - also referred to as milk sugar
is found most notably in milk. Lactose makes up around 2
8% of milk
(by weight). Maltose and lactose are less important as primary
fermenting sugars but may be used in combinations with common sugar
to bring extra flavor.
About 1 g (0.1%) of dextrose per
1 kg of meat lowers pH of meat by 0.1 pH. This means that 10
g of dextrose added to meat with initial pH value of 5.9 will lower pH
by one full unit to 4.9. Sugar levels of 0.5% - 0.7% are usually added
for reducing pH levels to just under 5.0.
When using acidification as a main
safety hurdle, salami is microbiologically stable when
pH is 5.2 or lower and this normally
requires about 48 hrs fermentation time for fast-fermented product
and 72 - 96 hours for medium-fermented type. In slow-fermented
salami pH does not drop lower than 5.5 but the sausage is microbiologically
stable due to its low moisture level (prolonged drying).
4. Water activity
(Aw) is an indication of how tightly water is "bound" inside of a
product. It does not say how much water is there, but how much is
available to support the growth of bacteria, yeasts or molds
(fungi). Adding salt or sugar "binds" some of this free water inside
of the product and lowers the amount of available water to bacteria
which compete very poorly with salt. Molds are very good
competitors for free water. We could make Aw lower by lowering the
temperature of the product but that is not practical as the
temperatures for making fermented sausages are well defined. A much
better solution is to lower water activity by drying.
Below certain Aw levels, microbes can not grow.
USDA guidelines
state:
"A potentially hazardous food does not include . . . a food
with a
WATER ACTIVITY value of 0.85 or less."
Aw measuring instrument by Decagon,
http://www.decagon.com
Common spoilage organisms and their Aw limits for
growth
Microbial Group
Example
aw
Products Affected
Normal bacteria
Salmonella species,
Escherichia coli
0.95-0.93
Fresh meat, milkAnimal intestinal tracts, unchlorinated
water
Clostridium botulinum
0.91
Meat, soil
Staph. aureus
0.89
Skin, red
meats, poultry
Normal yeast
Torulopsis species
0.88
Fruit juice concentrate
Normal molds
Aspergillus flavus
0.80
Jams, jellies
Halophilic bacteria
Wallemia sebi
0.75
Honey
Xerophilic molds
Aspergillus echimulatas
0.65
Flour
Osmophilic yeast
Saccharomyces bisporus
0.60
Dried fruits
Air drying is the process employed in lowering water
activity (moisture removal) and has to be properly controlled
otherwise it may lead to a number of defects including a total loss
of product.
During the long drying process of salami, the original
hurdles lose some of their original strength as the nitrite is depleted
and the number of lactic-acid bacteria decreases and the pH increases.
This is offset by drying which lowers water activity by removing moisture and the sausage
becomes more stable in time.
When using drying as a main safety hurdle salami is
microbiologically stable when Aw
is 0.89 or lower.
The drying chamber should not be overloaded as a uniform
air draft is needed for proper drying and mold prevention.
5. Smoking may or may not be utilized in a production
of fermented sausages. It has been used in countries in Northern
Europe where due to colder climate and shorter seasons, the drying
conditions were less favorable than in Spain or Italy.
Smoking imparts a different flavor, has some effect of fighting
bacteria, especially on the surface of the product and thus prevents
growth of molds on fermented sausages. Mold is desired on some
traditionally made Italian salamis and obviously smoking is not
deployed. Smoking temperature must correspond with
temperatures of fermenting and drying and in traditionally made
sausages, cold smoke of less than 22º C (70º F) is applied
after fermentation stage. Cold
smoking is after all "drying with smoke".
Use of Spices in
Fermented Sausages
Throughout history spices were known to possess
antibacterial properties and cinnamon, cumin, and thyme were used in
the mummification of bodies in ancient Egypt. It is hard to imagine
anything that is being cooked in India without curry powder
(coriander, turmeric, cumin, fenugreek and other spices). Latest research establishes that spices such as mustard,
cinnamon, and cloves are helpful in slowing the growth of molds,
yeast, and bacteria. Garlic and clove are effective against some
common strains of E.coli. Spices alone can not be used as a hurdle
against meat spoilage as the average amount added to meat is only about 1% (1
g/1 kg). To inhibit bacteria the amounts of spices will have to be very large
and that will alter the taste of the sausage. Rosemary and sage
have antioxidant properties that can delay the rancidity of fat. Marjoram
is a proxidant and will speed up the rancidity of fats.
To see which spices are known to offer some
protection against pathogenic (dangerous) bacteria go to:
safety hurdles
More on the use of spices in making sausage section
at : spices
Manufacturing
Technology
The first
manufacturing steps such as meat selection, grinding, mixing and
stuffing are common to all sausages whether fresh, smoked or fermented
types. After being stuffed with meat the fermented sausages are
submitted to different steps:
conditioning (optional)
fermenting
drying
storing
Conditioning is an
optional step for a home sausage maker and he has to exercise his own
judgement. In commercial plants the process of grinding, mixing and
stuffing salami is undertaken at a low temperature (0º
C, 32º
F) and as the
cold sausage is placed in a warmer (fermenting/drying) room, not
needed
condensation will appear on the surface of the sausage. The sausage must
remain there for 1-6 hours (depending on its diameter) at low humidity
(no air draft) until the
moisture evaporates. Then we can start the fermentation process. If the
sausage casing is dry there is no need for conditioning. It should also
be very carefully monitored (or even eliminated) in small diameter
casings which can dry out too quickly on the surface. This will
eliminate moisture (food) for lactic bacteria and they will not reduce
pH within the outer layers. As a result the sliced sausage will have a
different color in its outer layer (see effects of too fast drying
above).
Fermentation refers to
the production of lactic acid and to produce consistent quality product
parameters such as temperature, humidity and air flow should be
carefully monitored. The humidity in a drying room is increased to about
92-95 % and the temperature is increased to 18º
-26º
C, (66º
-78º
F). The
temperature range depends on the type of the sausage produced (fast,
medium or slow-fermented) and the type of the starter culture used. The
air flow is kept about 0.8 m/sec. Commercial plants monitor Aw (water
activity) of the sausage and readjust the correspondingly humidity level of
the drying chamber. There is normally a difference of less than 5% between
moisture level of the sausage and relative humidity of the room, the
latter figure being lower. This means if the Aw of the sausage is 0.95,
the humidity is set at 90%. Then when Aw drops to 0.90, the humidity
drops to 85% and so on.
When the fermentation starts
the main hurdles against microbiological spoilage of the sausage are the low
bacteria count of the meat, the presence of nitrite and salt. Keep in mind
that in time the sausage will be losing more and more moisture but the salt
remains inside and the percentage of salt in a finished sausage will be
higher. In about 48 hours lactic
bacteria metabolize enough sugar to produce a sufficient amount of lactic
acid to drop pH (increase acidity) of the sausage and this
stabilizes the sausage making it more resistant to spoilage.
Drying is a very important process
especially in the initial stages of production.
One may say why not to dry a
sausage very fast which will remove moisture and be done
with all this pH stuff and bacteria. Well, there are basically two
reasons:
1. The outside layer of
the sausage must not be hardened as it may prevent removal of the
remaining moisture. It may effect the curing of the outside layer which
will become visible when slicing the sausage (see the drawings below).
2.
Naturally existing in meat, bacteria and/or introduced starter cultures
need moisture and some time before they can metabolize sugar and
produce lactic acid which lowers pH. They are not going to multiply in
one second and start heavy production of acid. Similar to yeasts used to
ferment wine, these bacteria need some time to accomodate themselves in
this new environment, they keep on eating sugar and only
then comes a moment when they say OK, let's do some serious work.
Even if we could rapidly dry out the sausage without hardening its surface this will inhibit
beneficial bacteria from doing their work by removing moisture which
they need. The only possibility will be
to lower pH using chemical reactions such as adding GDL or citric
acid. This method does not depend on bacteria but unfortunatelly it will
add so much acidity that the product will not be edible. Moisture
removal during fermentation (it is a part of drying) must proceed slowly
and in a manner that will not inhibit work of beneficial bacteria.
Well balanced conditions for drying. The sausages are
drying from inside out and the moisture removed from
the surface is replaced by the moisture coming from the
inside of the sausage. For the perfect drying the humidity
of the drying room should be 5% lower than the water
activity (Aw) within the sausage.
Too fast moisture removal. It is like a
faster car pulling away from a slow one. Inside moisture
travelling towards the surface can not keep up with the
moisture removed from the surface. The sausage becomes dry
on the outside and moist inside.
The pronounced effect of fast drying.
The surface is dry and there is a visible grayish ring on a
sliced sausage. If the surface hardening occurs in the first stages
of drying the inside moisture may be permanently trapped and
bacteria will multiply spoiling the sausage.
In a course grind meat the moisture has more free room
and shorter distance to the surface. In a fine grind the
particles are very small and moisture has to overcome more
surface area on its way to the surface. Its path is longer.
This problem is magnified in a large diameter salami where
moisture has a much longer distance to travel to the surface
and a large diameter salami should be dried at a slower pace
and much longer than a small diameter one.
Water activity (Aw) can be lowered faster in a sausage
which contains more fat than a leaner sausage. Fat does not contain
water and a fatter sausage having proportionally less meat also contains less water. It will dry out faster.
Drying basically starts
already in the fermentation stage and the humidity is kept at a high
level of about 92%. Air flow is quite fast (0.8 m/sec) to permit fast
moisture removal but the high humidity level moisturizes the surface of
the casing preventing it from hardening. After about 48 hours
the fermentation stage ends but the drying continues to remove more moisture
from the sausage. As the Aw has dropped lower the humidity level is
decreased to about 0.85-90%. Maintaining previous fast air flow may
harden the surface of the casing so the air speed is decreased to about
0.5 m/sec (1.8 miles/per hour-slow walk). The temperature is lowered to
create less favorable conditions for the growth of bacteria. At this
time the medium-fermented sausage will be finished.
Slow-fermented sausages require additional
drying time and the humidity is lowered again just to be a few percents
lower than the moisture content of a sausage and that falls into 75-80%
range. Air flow is decreased again to about 1 ft/sec. The temperature is
lowered to 15º
C (60º
F) to create less favorable conditions for the
growth of bacteria. At those conditions the sausage will remain in a drying
chamber for an additional 4-8 weeks, depending on the diameter of the casing.
Sausage is microbiologically stable and can
remain at the above settings for a very long time. It should be kept in
a dark room which will prevent color change and fat rancidity. There is
very little need for the air flow now and it can be kept to the minimum.
Some air flow is welcome as it inhibits formation of mold. The
temperature is set to about 10º
-15º
C, (50º
-60º
F). The humidity should remain
at about 75% as lower humidity will increasing drying and the sausage
will lose more of its weight. Much higher humidity levels may create
favorable conditions for development of mold. If any mold develops it
can be easily wiped off with a solution of water and vinegar. The
sausage can also be cold smoked for a few hours which will inhibit the
growth of a new mold. At these temperatures and humidity levels, the
sausage has an almost indefinite shelf life. Depending on the method of manufacture
(drying time), diameter of a casing and the content of fat in a sausage
mass, fermented sausages lose from 5 - 40% of its original weight.
Jumbo Display Thermo-Hygrometer that measures temperaute and
humidity at the same time made by DeltaTRAK
http://www.deltatrak.com
Only 3.85" (W) x 4.33" (H) x 0.82" (D), available from QA Instruments,
http://www.qasupplies.com/
A typical medium-fermented salami
process
Process
Temp
Humidity%
aw
pH
Air speedmeter/sec
Time
º C
º F
Conditioning
20-25
68-77
< 60
0.96-0.97
5.8
0
< 6 hours
1. Fermenting
18-25
66-77
98-92
0.94-0.96
5.6-5.2
0.8
2 - 4 days
2. Drying
18-22
66-70
85-90
0.95-0.90
5.2-4.8
0.5
5 - 10 days
3. Drying
15
59
75-80
0.85-0.92
5.0-4.6
0.1
4 - 8 weeks
Storing
10-15
50-59
75-80
< 0.1
in a dark room
Notes:
The speed of
3.6 km/h
(2.2 mile/hour) corresponds to the speed of 1 meter/second.
Based on parameters in the table above, a medium-fermented salami
will lose about 1.0 - 1.5% of its mass daily.
Depending on the
manufacturing method salamis can be divided into:
Fast-fermented
Medium-fermented
Slow-fermented
Inexpensive, low quality,
shortest shelf life, strong tangy and sour taste.
Production time: 5-7 days
The technology of this product is based on a fast
drop of pH (below 5.0 in just 2 days) to make it stable.
The pH of a finished sausage is about 4.6-4.8
making it safe. Water activity (Aw) is of a
lesser hurdle as there is not enough time to
remove enough moisture by controlled drying. Aw of a
finished sausage is about 0.92.
Lowering pH is accomplished by the addition of fast
acting sugar (dextrose) and/or GDL (glucono-δ-lactone)
plus fast-acting starter cultures. The flavor is
greatly influenced by the acidification of the sausage
and spices employed.
Temperatures: Initial fermentation
temperatures are quite high 26º
-30º C,
(78º
-86º
F) to allow
rapid growth of fast-acting starter cultures. Some very
fast cultured are targeted for fermentation temperatures
up to 45º C (113º F).
Sodium nitrite (Cure 1) is used as the first hurdle
against bacteria spoilage. Nitrate is not used as
there is not enough time for it to release nitrite.
Better quality, less sour
and generally better
salami flavor than that of a fast-fermented sausage.
Production time: 4-6 weeks
The technology of this product is based on a moderate
drop of pH (below 5.0 in about 4 days) and is about
4.8 in a finished sausage. The
production time is long enough to dry out enough
moisture so that water activity (Aw) level of 0.93 is
achieved making it resistant against
Salmonella
and Staph.aureus. The flavor of the
finished product is due to acidification, addition of
spices and to a smaller extent (insufficient drying
time) to some natural processes (proteolysis and
lipolysis) within a sausage.
Temperatures: Temperatures of
22º
-25º
C, ( 70º
-77º
F)
are applied during the initial fermentation stages and
at those temperatures fast-acting bacteria cultures
perform a bit slower.
Sodium nitrite (Cure #1) is added being the first
hurdle against bacteria spoilage. Nitrate is not needed
as the production times are still relatively short.
High quality, traditionally
made salami with a superior salami flavor. They are
never fully acidifed and that is why there is little of a sour and
tangy flavor so pronounced in a fast fermented types.
Salamis develop a desired, classical salami flavor,
somewhat cheese and moldy, due
to a long drying period which permits for many of
the natural biochemical reactions to take place inside
of the meat.
Production time:
6 weeks or longer for a 45 mm
casing (a very large diameter salami can take 5, 8
months or
even a year to dry).
The technology of this product is based on the drying
process (lowering Aw-water activity) and on very
slow drop in
pH (almost never dropping to 5.2) which will later reverse (increase) as the
drying progresses. Slow drop in pH gives
Micrococcus bacteria sufficient time to
react with nitrate. As a result nitrate releases nitrite
which is necessary for:
control of Cl.botulinum
proper color of the sausage
improved flavor
The Aw of a finished sausage is between 0.82-0.88
and the pH of a finished sausage is about 5.3-6.0 (the
initial pH value of the meat used for processing is
about 5.8). Although this final pH value might
seem to be high the sausage is microbiologically very
stable due to its low moisture content (low Aw).
Temperatures: Temperatures of
16º
-20º
C, (62º
-68º
F)
are applied during fermentation stage.
Sodium nitrate or sodium nitrite and nitrate
(Cure
#2) are added.
Bactoferm™ HLP
Bactoferm™ F-RM-52
Bactoferm™ T-SPX
Bactoferm™ HLP -
fast culture targeted for
fermentation temperatures of 90º -115º F, 30º -45º C.
Use
dextrose.
Bactoferm™ F-RM-52
-
medium fast culture
targeted for fermentation temperatures of 22º -32º C (70º -90º
F)Use dextrose.
Bactoferm™ T-SPX -
slow culture for making
traditional sausages and targeted for temperatures not
higher than 24º C (76º F).Use sugar.
Bactoferm™
F-LC
Bactoferm™
F-LC
Bactoferm™
F-LC - meat culture with bioprotective
properties for production of fast or medium-fast fermented
sausages where a higher count of
L.monocytogenes bacteria may be
suspected. Recommended fermentation
temperature is 20º -24º C (68º -75º F) for at least 48 hours.
Use dextrose as this culture ferments sugar slowly.
Once the temperature drops below 25º C
(77º
F) the cold smoke can be applied which contributes positively to the flavor
and inhibits mold growth. No more drying is needed and
the sausage can be sold.
Mold is usually applied after 2-3 days by spraying or
dipping sausages in a mold solution.
Salamis which are produced without mold on its
surface can be cold smoked after 48 hours which is
basically drying with a thin smoke.
Above listed is
a partial only list of starter
cultures made by the Danish Company "Chr. Hansen",
www.chr-hansen.com
.They are available from Butcher Packer,
www.butcher-packer.com
Higher temperatures speed up
bacteria growth which results in:
faster pH drop due to increased lactic acid
production
faster development of strong curing color
faster rancidity of fat which is an unwelcome
scenario especially in slow-fermented products that are stored
for long time
Starter Cultures
In the past fermented sausages were made by using natural flora
(bacteria) of the establishment. Which is fine even today for a home
based sausagemaker or a small plant. A commercial producer can not relay
on mother nature to produced a constant quality product and he has to
eliminate any possible risks that may come up. He has to control
parameters pH of meat material, sausage pH, water activity Aw,
temperature, air speed and bacteria. For a meat plant making a thousand
pounds of sausages a day it is out of the question to rely on natural
bacteria to start the fermentation process and this is where starter
cultures come into play.
This is similar to the wine making process:
originally wine was made by leaving fruit
with water to start fermenting
then we started to add wine yeasts
which were produced in tightly controlled laboratory conditions.
The wine was being fermented using its own fruit yeasts
plus added starter cultures (wine fermenting yeasts)
commercial wine makers do not want ANY yeasts
that reside in fruit as that will not produce a constant quality
product. In the first stage of a production process a chemical is
introduced that will kill all yeasts present in the fruit and
then after a day commercially produced wine fermenting yeasts
are introduced into fruit and water.
In meats we don't introduced chemicals to kill
bacteria but we have these options:
use meats with the initial bacteria count of
100-1000 per gram of meat
use laboratory grown starter cultures
There are many manufacturers of starter cultures that
are used in Europe and in the USA and we are going to list products made by
the Danish manufacturer "Chr. Hansen" as their products are easily
obtained from American distributors of sausage making equipment and
supplies, for example Butcher Packer
www. butcher-packer.com
Some typical starter cultures are listed in the table
below. In addition to starter cultures whose main purpose is production
of lactic acid, there are two cultures that are very useful:
Bactoferm™
F-LC
M-EK-4 Bactoferm™
Meat culture with bioprotective
properties for production of fermented sausages with short
production type where a higher count of
L.monocytogenes bacteria may be
suspected. Bactoferm™ F-LC has the ability to control
listeria at the same
time as it performs as a classical starter culture for
fermented sausages. The culture produces pediocin and
bavaricin (kind of "antibiotics") and that keeps
L.monocytogenes at safe
levels. Recommended fermentation temperature is 20º -24º C
(68º -75º F) for at least 48 hours. Use dextrose as this
culture ferments sugar slowly.
Meat culture for production of
molded dried sausages with a white/cream colored
appearance. M-EK-4 is particularly recommended for the
production of traditional sausages dried at low temperatures
and/or low humidity. M-EK-4 suppresses the growth of
undesirable organisms such as indigenous molds, yeasts and
bacteria. The culture has a positive effect on the drying
process by preventing the emergence of a dry rim.
Furthermore, the mold degrades lactic acid during
maturation resulting in a pH increase and a less sourish
flavour.
Salamis with
a surface mold
In many European countries (France,
Italy and others) it is a normal occurence to see a salami with a white
surface mold. This is how it has been made for hundreds of years, the
mold is intentional and it contributes to the wonderful flavor of the
sausage. It also protects the sausage from the effects of light and
oxygen which helps to preserve color and slows down rancidity of fat.
Mold covered salamis are not smoked as the smoke application will
prevent molds from growing on the surface. Cold smoking sausages (below
25º C,
78º
F) after fermentation (after around 48
hours) will prevent mold from growing on
its surface. Mold can be removed by wiping it off with a rag soaked in
vinegar solution. The color of the mold should be white or
off-white and not yellow, green, or black. As mold in time can grow
to a considerable length it is brushed off before sale.
Sausages that are made nowadays are dipped
into a mold solution or have a mold solution sprayed on the surface. The
factory grown molds such as the M-EK-4 Bactoferm™
described in table
above are easily obtainable which permits the
growth of a constant quality intentional mold.
Optimal conditions for
the growth of mold are: warm temperatures, no air draft and over 75%
humidity.
To prevent growth of
mold the commercial producers dip the sausage after filling for a
few seconds into 10% solution of potassium sorbate.
Salami Flavor The flavor of salami is largely dictated by the manufacturing method
(fast, medium or slow-fermented). In fast-fermented products the
economics play the major role and the product must be made fast and
cheap. There is little reason to produce high quality salami or
pepperoni that will end up as a pizza topping. Most super market sold
salamis are fast-fermented sausages. A fast fermented product is based on
the rapid drop of pH (increasing acidity) and that inevitably leaves a sour
and tangy acidic flavor. Spices come to play an important role as their
part is to offset this sourness. Applying smoke will add in bringing a
new flavor.In slow-fermented traditionally made
salami the flavor is the result of many microbiological reactions that
take place in many months of its production. Lactic bacteria process
sugar much slower than dextrose which leads to a slow pH drop. Most of
sugar is converted into lactic acid but as temperatures drop so does
the activity of bacteria which leads to a very slow pH drop. As a result complex
biological reactions that are taking place with remaining sugar create a
different salami flavor. Spices play a lesser role
as spices lose their flavor in time anyhow. There is no sourly flavor
as in slow-fermented products pH is known to increase (less acidity) to
quite a high value (6.0) in time. The flavor is kind of cheesy, very
typical of a traditionally made product. Salamis with mold will have
distinctive cheesy-moldy flavor.
Making Fermented Sausages at
Home
If you have read the sections above you should have a pretty good
understanding of the subject by now. At least you know how it should be
made according to the rules of the meat science. To make consistent
products parameters such as temperature, humidity and air speed must be
continuously monitored and adjusted and this is exactly what modern
drying chambers do. It is not expected that one
will invest into sophisticated drying chamber with temperature, humidity
and air flow controls and the technology of making fermented sausages
has to be somewhat modified and adapted to the local conditions of the
home sausage maker. Fermented sausages were made in Europe for
thousands of years without all this technology and they tasted great.
Yes they were made, but not during all 12 months of the year. They were made when
the temperature and humidity were right and some moderately blowing
wind was of immense help, too (Italy, Spain). You can find a window of
opportunity for making fermented sausages everywhere: in the summer in
Alaska, in the winter in Florida. Ever heard of Summer Sausage? It was
not made in summer when temperatures are high and humidity is low. It
was made in winter when temperatures were lower and humidity was high,
then it dried and was eaten in the summer when harvesting crops.
As long as we remember that in the first stages
of production the temperatures are higher and the drying chamber must
have a bowl of water to create high humidity levels we can produce a
fermented sausage. Then as the process
progresses the levels of humidity and temperature settings can be
lowered. Cures (cure #1 or Cure #2) are an absolute necessity and
commonly available and inexpensive starter cultures will guarantee a
successful quality product.The above tables provide all information that is necessary
to produce a fermented sausage. At home conditions there are basically
two stages:
Fermenting which
lasts about 48 hours
Drying which may
be subdivided into:
fast-fermented type
- 5-7 days
medium-fermented
type - 4-6 weeks
slow-fermented type
- 6 weeks or longer
It is impossible to provide exact drying times as these
will depend on the size of the casing, percentage of the fat, temperature,
humidity, air draft, how full is the drying room and so on. Nevertheless the above figures may be
considered to be a rule of the thumb values which provide a point
of reference. The rest is trial and error and gaining experience. You
will find in many sources advice such as: this is how I like to do it,
I have been doing this that way and it worked for me and so
on....without any concrete data to temperatures, humidity or air speed.
Instead of writing about what works for us we have decided to create the
table which shows how salamis are made commercially in accordance to the
rules of meat science. It will be unrealistic to expect that a home
based sausage maker will have enough equipment at his disposal to
measure all those parameters. Nevertheless he will have a valuable point
of reference and he will be able to improvise his production according
to what he has and what he can do in order to make his salami making
process as close as possible to the recommended data. For instance,
temperatures might be too high and humidity too low to dry sausages in
summer time in hot climatic zones and in those areas winter time is more
suitable. If a drying chamber is available (old refrigerator, a suitable
box, etc.) a dish filled with water will provide more humidity. So will
a wet rag. Nothing will happen if sausages are removed every 3-4 hours
from the drying chamber and showered with water for a few minutes.
Water will moisten the surface of the sausage and prevent it from too
rapid drying. To control air speed think of a home made smokehouse and
its draft control. The air enters with smoke into the smoking chamber,
raises up and escapes the chamber through the exit pipe on top which has
a draft control. If its fully open you have full draft (full air speed),
if it is open 1/4 there is 1/4 of the draft. In a smokehouse the reason for
this air draft is to remove moist air that accumulates in the upper
parts of the chamber. If it was not removed the sausages will taste
rancid and bitter and the color will be very dark due to accumulation of
soot and other unburnt particles. In making fermented sausages,
evaporating moisture must also be removed otherwise it will create
favorable conditions for the growth of mold and we may not need this. If
the drying chamber is fully enclosed without any natural draft, one can
open the door to it every now and then and allow the moisture to escape.
We all know the smell of a refrigerator when we open it after coming from
extended vacation and the drying chamber is no exception.
Salami making process
Raw material:
pork pH-5.9
beef pH-5.8
Aw, 0.98-0.99
Temperature
Humidity in
%
Air-speed in
m/sec
Time
Expected pH
Expected Aw
º C
º F
Conditioning
20-25
68-77
60-70
1-6 hours
little change
little change
1. Fermenting/drying
18-25
66-77
92-95
0.5-0.8
2-4 days
5.2-5.6
0.94-0.96
2. Drying
18-22
66-72
85-90
0.2-0.5
5-10 days
4.8-5.2
0.90-0.95
When the sausage achieves pH acidity
value 5.2 or lower or water activity Aw 0.89,
it is considered microbiologically stable and it is safe to
consume. This will be a fast fermented product. This does not
mean that the process must be stopped. The drying can
continue, the sausage will lose more moisture and weight
and its shelf life will be longer.
3. Drying
15
60
75-80
0.1-0.2
4-8 weeks
4.6-5.0
0.85-0.92
When the sausage achieves pH acidity
value 5.2 or lower or water activity Aw 0.89,
it is considered microbiologically stable and it is safe to
consume. This will be a medium fermented product. This does
not mean that the process must be stopped. The drying can
continue, the sausage will lose more moisture and weight
and its shelf life will be longer.
Storing
10-15
50-60
70-75
0.05-0.1
more than 8 weeks
will increase up to 6.0
0.85-0.89
During the storage period the pH value of
the sausage will increase, the sausage will be less acidic
and its flavor will be more mellow. Less acidic and more
cheesy. Sausage will lose more moisture and if kept at
those conditions in a dark room, it will have an almost
indefinite shelf life.
USDA guidelines
state:
"A potentially hazardous food does not include . . . a food
with a
WATER ACTIVITY value of 0.85 or less."
Notes:
The speed of
3.6 km/h
(2.2 mile/hour) corresponds to the speed of 1 meter/second
which is basically a walking speed.
Traditionally fermented salami can be made without
starter cultures and the fermentation is caused by
the bacteria naturally present in meat. It will be only
microbiologically stable when Aw reaches 0.89 as
its pH value never drops to 5.2
Traditionally fermented sausages very seldom achieve
pH level of 5.2 due to smaller amounts of regular sugar
(sucrose) used and the absence of starter cultures
although some cultures (Bactoferm™ T-SPX)
are designed for
slow-fermented products.
Fast and medium-fermented salamis achieve lower pH
value due to the use of GDL, fast fermenting sugar
(dextrose) and fast acting starter cultures.
Making fermented products is a combination of art
and sausage making and one will be ill advised to start with a
traditionally slow fermented product which is made without any
starter cultures. On the other hand slow and medium fermented
products are much easier to make and gained experience can lead to
production of slow-fermented sausages.
Notes:
Smearing of the fat
(dull knife or warm fat) should be avoided as it will clog the
inside passages of the casing and inhibit moisture from escaping
which will affect drying.
Starter cultures
must be kept frozen and should not be mixed with other
ingredients until ready to use. Other ingredients such as salt,
sugar, spices or others will always contain some moisture which will
trigger reaction with starter cultures. Starter cultures are after
all bacteria that needs only higher temperature, humidity (moisture)
and food (sugar) to start multiplying.
To keep humidity at
high levels, the sausages may be showered a few times a day for a
minute or two.
Some air draft should be present even in the
final months of drying to prevent mold creation.
Salami
Recipes
By choosing an appropriate starter culture a
fast, medium or slow-fermented sausage can be produced, even if
the recipe remains the same. It
will have different texture and flavor but as long as the
rules are followed it will always be a quality sausage.
Hungarian Salami - traditionally fermented salami
without starter cultures. This
is the real recipe with instructions on making a traditional slow
fermented salami and in 1950 - 1990 thousands of pounds of this
sausage were made by Polish meat plants and sold to the
public.
Polish Salami - non-fermented, baked and air-dried salami
without starter cultures
Metka - Polish spreadable raw sausage (German Mettwurst family),
without starter cultures
Salmon Metka - Polish spreadable raw sausage (German Mettwurst
family), without starter
cultures
Fuet - Spanish dry cured salami
Nham - Thai fast-fermented pork sausage
Chorizo - Spanish dry sausage
Page added on
April 6, 2008.
This section will be expanded in time and photos will be added.
Copyright © 2008 WedlinyDomowe.com All rights reserved
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